G5.22  Be careful with the sign conventions for the angles.  See LB pages 902/903 for a careful discussion.  Griffths is NOT careful in Example 5.5 and ends up with a non-standard convention for the signs in 5.35. Compare with LB 28.5 which uses the standard convention.
G5.41  You will need to assume that the particle's initial velocity has no z-component.